@hackminded I've tried minimizing Vivaldi every way that I know of on OS X 10.11.6, including hiding it and minimizing to the application icon, and I can't replicate this nor have I ever experienced it. What version of macOS are you running?

Hello @xyzzy there was actually a mistake on my part. The issue is not when I minimize, but when I close Vivaldi. I have set my Vivaldi to re-open the last session once exited. THIS works perfectly when I force quit using CMD + Q and all my tabs are restored. However, when I quit using the close button it just loses all tabs and resets to start page.

@hackminded One of the unique things on a Mac is that closing all windows (usually) doesn't actually close the application itself. If you close all Vivaldi windows, there's still a dot next to Vivaldi's icon in the Dock meaning that the Vivaldi application is still running.

So... when you closed your Vivaldi window, your tabs got closed with it, Vivaldi was left running, and clicking the Vivaldi icon (with the dot next to it) in the Dock simply opened a new window with the Vivaldi Start Page.

On the other hand, hitting Command-Q (or using "Vivaldi / Quit Vivaldi") is the equivalent of politely asking Vivaldi to close; Vivaldi saves its state, shuts down, and the dot disappears from the Vivaldi icon in the Dock. Clicking the Dock icon relaunches Vivaldi. In your case, it restores your last session on launch.

(By the way, a "Force Quit" is something else in the Mac world. If an application gets stuck and becomes TOTALLY unresponsive, and does not shut down when you press Command-Q, you can right-click on its Dock icon to "Force Quit" the application. However, that action terminates the application's process abruptly and forcibly, and (most likely) will result in data loss. "Quit" is like shutting down your computer; "Force Quit" is like pulling the power plug.)

Thanks for posting the video; it was very helpful. Hopefully it's a bit more clear now that Vivaldi really is working as it should (on a Mac) even though it behaves differently on other platforms.

If you ever have any more questions or need any further clarification, please feel free to ask. We're all here to help each other out.

@hackminded No problem. Yes, that's correct. Quit Vivaldi using either "Command-Q" on the keyboard or by clicking "Vivaldi" on the macOS Menu Bar and then selecting "Quit Vivaldi" from the dropdown menu.

... and welcome to the Mac! FYI, Apple has some great tips on their web site to help familiarize you with macOS and to ease your transition from other operating systems.